Brake testing apparatus



Feb. 16, 1937, F. H. STROUD BRAKE TESTING APPARATUS 3 Sheets-Sheet 1 Filed May 5, 1931 A4 Tum/v5 r Feb. 16, 1937. F, H, TR UD 2,070,873

BRAKE TESTING APPARATUS Filed May 5, 1931 3 Sheets-Sheet 2 4] 7 f I A6 A 1/ 9 27 "III I Feb. 16, 1937. F. H. sTRo-u: 2,070,373

BRAKE TESTING APPARATUS Filed May 5, 1931 v 3 Sheets-Sheet 3 11v I/ENTOR f. Sfraur? A TTORNEY Patented Feb. 16, 1937 HPAT'ENT OFFICE i 2,970,873 v j BRAKE TESTING APPARATUS Francis H. S troud; Seattle, Wash, assignor ta .Weaver Manufacturing Company, Springfield,

111., a corporation of Illinois Application May 5, 1931, Serial No. 535,124

of apparatus wherein movable platforms are subjected; 'in opposition to compression springs or the like; to the force of inertia impartedfrom the braked wheels of a vehicle-body passing thereover, the object, generally stated; being the provision of more serviceable and'emcient mechanism for thispurpose than heretofore devised;

provision of means eliminating extensive calioration servicing such as has been heretofore required where the brake efliciency of the respective vehicle wheels is determined by actualmovement rather than by the force of momen- A further object resides in the accommodation to a retention of the movable platform inplanes constantly maintained parallel, in such wise im-' parting substantially uniform force to the operative mechanism throughout platform movement.

Fundamentally,- the primary objective towards' a determination of actual braking efliciency of the respective vehicle wheels in opposition to the vehicle's momentum is achieved in the instant invention by a gauging of the recoil rather than the forward movement of the compressed member, such recoil being necessarily proportionate to the actual force of compression as distinguished from a gauging of the movement of compression which necessarily varies responsive tothe innumerable physical elements which may enter. I

The above, together with further and more particular objects and advantages will, 'itls believed, become apparent throughout the course of" the following detailed description and claims,

the invention consisting in the novel construction,-a'daptation and combination of parts hereinafter described and claimed.

In said drawings, Figure l is a top plan view of apparatusembodying the present invention, representing by dotted lines the rlativerelationships of the op- 1 crating structure therebel'ow.

Fig. 2 is a longitudinal vertical section taken on the line 2-2 of Fig. 1.

Fig; 3 is anenlarged ,fragmentarily represented transverse vertical section thr ough of Fig. 2,

parts beingjbroken away.

Fig. 4 is a fragmentary longitudinal verticalsection on line 44 of Fig. 3.

Fig.5 is a transversevertical' section through 5-5 of Fig. 2, taken to an enlarged-sealer Fig. 6 is an enlarged transverseverticai section 1 looking in the opposite direction to that of Fig. 5

through Bj6 of Fig. 2. r

Figure '7 is a front elevation indicating the assembly of the indicating gauges for the respective platforms; and

Figure 8 is a vertical section taken an enlarged-scalethrough 8-8 of Figure'i. A more specific object of the invention is the I The invention contemplates the use of four individually operative platforms so spaced as to ciated mechanism therewith incorporating: similar structure, theillustrative disclosure is confined to the showing of one.

Reference being had to said drawings, the numeral 1 represents a supporting body set into and suitably mounted for a flush disposition of the surface 8 thereof with'the floor of a garage. service station, or the like, said frame centrically apertured as at I 0 for the reception of a longitudinally-movable platform 9 having a gripping surface'preferably provided by a concrete bed H.

Said platform is, moreover, conformed to provide down-turned lugs 12 presenting bifurcate recessedcorners accommodating the reception of the fork arms l3 of supporting members I4, said members respectively fulcrumed at lower terminalsby cross shafts l5 received in depending laterally disposed bearings of the supporting body.

ing the stud of a longitudinally adjustable thrustmember l9 carried by. frame 1, interposition of said spring therebetween and a depending strut 20 integral with the platform 9 normally maintaining the latterin its inoperative rearmost disposition represented in the respective views.

More particularly to operating m echanism serving to determine the recoil force from. the compressed disposition of said spring, the invention provides atthe oppositional end of said frame, a cylinder 23 secured as by bolts to a rigidly supported chambered head 24 integrally secured to the supporting body. Said cylinder communicatesthrough an elongated throat 21, with a pair of outlet ports 2t leading from the reservoir 25 of. said head. Insertable through apertures closable by plugs 23, 23 indicates check valve assemblies for the respective ports.

As herein designed, said reservoir is of an approximate U-shaped configuration in transverse vertical section. Vented filler plugs received in respective arms of said reservoir accommodate insertion of an oil or other desired fluid to the same.

3| represents a conduit connecting the port 32 of cylinder 23 with a suitable type pressure indicating gauge, a return passage 33 leading from said gauge to one arm of the head reservoir 25. 34 indicates a pressure release from the companion arm of said reservoir for the cylinder 23, suchoilas may pass the'ring of a cylinder-received plunger member 35 being recovered and returned thereby to the reservoir. A link connection 35 is represented between said plunger and the platform strut 20.

More especially with respect to the aforemen tioned indicating gauge, generally represented by the numeral 40, such may be of the'conventional expandible-tube character, that is, a spiral tube encircling and having an eccentric connection with the arbor 4| of an indicating hand 42, said hand being revolubly actuated over the gauge face responsive to expansion of the tube.

In connecting said gauges with the aforementioned conduits 3|, 33,-1 provide valvecasings 43 each having a pair oflead arms 43,45, both of which communicate through a chamber 46 with the expandible tube of the gauges. Such arms 44 receiving the respective conduits 3| w-hile.

thefother arm 45 connects with the respective pressure-release lines 33, I provide valves 41 serving to normally close the communicating passages 48 between said arms. 50 represents suitable packing glands and 5| a control shaft, cams 52. being supported thereby for dislodging the valves. 53 indicates a manually operated handle.

In operation, taking one wheel only as an example, the vehicle is allowed to. gain momentum and subsequently checked by braking the wheels prior to passage over the concretebed II of platform 9: The resultantforward momentum imparted tothe-latter compresses spring 2| to an.

extent proportionate 'to the braking resistance of the wheel. The: responsive suction stroke of plunger 35 dislodges check valves 23 from their of spring 2| upon the gauge; The resultant readings upon the gauges are noted in determining the relative brake adjustments required, subsequent to which thegauge control shaft 5| is actuated to motivate the cams into unseating the valves, relievingthe back-pressure on the'cylinder. Responsive to such pressure release, springs 2| assert their compression energy in forcing the oil behind cylinder 35 through conduit 3|, passage 43 of the valve casing, and conduit 33 to the receptacle 25.

As is believed evident, the recoil force of the spring is substantially identical. to the actual force imparted to the spring in compressing the same.

While the illustrative disclosure represents structure now preferred by me, it is not my in-' tention to confine the invention thereto, except as may be limited by the hereto annexed claims.

indicating a z plungers movable with the platforms, cylinders therefor, vented oil reservoirs having ports connecting the same with the cylinders, check valves normally closing said ports and adapted to open responsive to suction strokes of the plunger for admitting oil-to the cylinder, pressure-indicating' gauges for respective cylinders, and a conduit from each ofsaidgcylinders to the respective v pressure-indicating gauge-1 2. The apparatus as defined in claim 1, wherein V I is provided a return conduit leading from said gauge to the reservoir.

3. -In' brake testing apparatus, a horizontal platform arranged in the path of travel of a moving vehicle wheel and-having a friction surface comprising a body of cement-,; said platform supported formovement in'the' plane of the vehicle travel, being a compression, spring for said plate form arranged in opposition to the forward movement of the platform, a plunger movable with.

the platform, a cylinder therefor, a vented oil reservoir, ports, therefor connecting the same with the cylinder, check valves normally closing said ports and adapted to open responsive to suction strokes of the plunger-for admitting oil to thecylinder, a pressureindicating gauge, and;

a' conduit, from said cylinder, to, said pressure- 4. In brake, testing apparatus,"a horizontal-l-s platform arranged in the path of travel of a moving vehicle wheel and having means .supporting the platform for movement inthe plane of the vehicle travel, a compression spring for.

said platform arranged in opposition to the for-; ward movement of the platform, (of a.-plunger movable with the platform, a cylinder therefor,-

a vented oil reservoir havinga port, communicanormally closing said port,- said'valve being adapt.

50 tion from saidport to the cylinder,.a check valve. j

ed to open responsive to suction strokes of the plunger for admitting. oil to the cylinder, a pressure-indicating gauge and a conduit from said cylinder to said pressure-indicating gauge. 5. The apparatus as defined in c1aim..4,* the platform supportcomprisingmeans' for maintain-"- platform arranged inthe path of travel of, the

wheel of a moving vehicle and supported, for movement in the plane of the vehicle travel, a compressionsprin'g for saidplatform arranged in opposition to the forward movement of the plat-.

form, a plunger carried by said platform, a cylinf der for said plunger, an oil receptacle, means to admit oil from said receptacle to said cylinder responsive to suction strokes of. the plunger, 9'; pressure-indicating gauge, a conduit from said cylinder to said pressure -indicat'inggauge, and

means responsive to compression strokes of said plunger for imparting pressure of the oil in said cylinder to said gauge.

7. In brake testing apparatus, a platform arranged in the path of travel of the wheel of a moving vehicle and supported for movement in the plane of the vehicle travel, a compression spring for said platformarra'nged in opposition to vehicle momentum imparted to the platform, a plunger movable with'the platform, a cylinder for said plunger, means to admit a fluid to said cylinder responsive to compression of said spring, a pressure-indicating gauge, and means responsive to the recoil action of said spring for imparting the plunger pressure upon the fluid to said gauge.

8. In brake testing apparatus, a platform arranged in the path of travel of the wheel of a moving vehicle, said platform supported for movement in the plane of the vehicle travel, a plunger movable with the platform, a cylinder for said plunger, means to admit a fluid to said cylinder responsive to vehicle-impelled movement of the platform, means arranged in opposition to-sald fluid-admission movement of said plunger for yieldably resisting the same, and means operated by said fluid to indicate the effective force of said resistance.

9. In apparatus adapted to determine braking efliciency upon a wheel underv vehicle momentum, a platform movable responsive to frictional en gagement of the braked wheel, means to yieldably resist said platform movement, a cylinder, means responsive to the travel of said platform in opposition to said resisting means for admitting a fluid to said cylinder, and means operable by said "fluid spring yieldabl'y resisting said platform movement, means including a cylinder, a plunger therefor, and'a fluid admission means for said cylinder rendered operative responsive to compression of said spring, and means operated by said fluid for determining the resultant force of opposition of said spring to the platform movement.

11. In apparatus for determining the brake eiflciency upon a wheel under vehicle momentum, means movable responsive to frictional engagement of the braked wheel thereon, compression spring mechanlsm-yieldably resisting said movable means, and force-measuring means including a gauge arranged to resist the recoil energy of the spring mechanism for indicating the force of compression imparted by said movable means to the spring.

12. In apparatus for determining brake emciency upon a wheel under vehicle momentum, a platform movable responsive to frictional engagement of the braked wheel thereon, elastic means yieldably resisting said vehicle-impelled platform movement, and force-measuring means including a gauge arranged to oppose the rebound action of the elastic means for indicating the force imparted by the platform to the elastic means.

FRANCIS H. STROUD. 

